Personal Finance
Cost Per Mile Calculator
Add all trip costs and divide by distance for a true cost per mile or kilometre.
True cost per mile
Fuel alone understates driving cost. Parking, tolls, congestion charges and wear add up — this page focuses on the cash costs you enter for one trip or a regular route, then expresses them per mile (or per kilometre if you convert). Useful for expense claims, side-hustle deliveries and deciding whether a detour is worth the money. HMRC mileage rates are a separate allowance system for tax; they are not the same as your true cash cost. For fuel-only trips see fuel cost; for commuting patterns see commute cost; for mode choice see car vs train. Estimates only — not tax advice. Delivery and courier side hustles should recalculate whenever fuel jumps or parking rules change in the city you cover. Pooling errands into one loop lowers per-mile overhead because parking and tolls spread across more productive miles. Keep a simple log for a fortnight and replace estimates with your observed average before you set client rates.
Worked example
A 46-mile round trip uses £9.20 of fuel, £4 parking and you allow 8p/mile wear (about £3.68). Total £16.88 → about 36.7p per mile. If a client reimburses only 25p/mile you are subsidising roughly £5.40 on that run unless you renegotiate or batch jobs.
Limits and assumptions
Insurance and road tax are only included if you bake them into your per-mile wear figure. EV costing needs kWh and unit rates, not petrol mpg. Not an HMRC advisory tool.
Frequently asked questions
Is this the same as HMRC mileage rates?
No. HMRC rates are fixed allowances. This tool uses the costs you enter for a personal estimate.
Should I include depreciation?
For a fuller cost, yes — many people add a pence-per-mile wear figure. For pure cash this week, fuel and parking may be enough.
Can I work in kilometres?
Convert miles ↔ km (1 mile ≈ 1.609 km) and keep the distance unit consistent with your cost basis.
How do tolls fit multi-stop days?
Add tolls to the day’s total cost, then divide by total miles driven that day for a blended per-mile figure.
What about passengers sharing fuel?
Divide the trip’s cash cost by people before converting to per-mile if you only care about your share.